The invention concerns a method of increasing the output of a transfer film upon embossing, in particular hot embossing, wherein the transfer film has a carrier film and a transfer layer portion which is releasable from the carrier film, wherein during a first embossing operation first regions of the transfer layer portion which are arranged removed from each other at a spacing a are transferred by means of a first embossing tool from the transfer film onto at least one substrate, wherein first openings are produced at the spacing a in the transfer layer portion of the transfer film.
In the operation of embossing on cards of paper or plastic material for the mass production of bankcards, credit cards, telephone cards, driving license cards, identity cards and the like, regions of a transfer layer portion of a transfer film are embossed onto a card substrate by means of known card production apparatuses, for example of the “Cardline” type from Atlantic Zeiser, with up to 40,000 cards per hour being embossed. To achieve such high levels of embossing output a hot rolling embossing method is usually employed, in which an embossing wheel whose surface has raised segments in the shape of the regions to be embossed out of the transfer layer portion of the transfer film is used. The embossing wheel is also usually followed by a cooling device to which the embossed card substrate and the transfer film still adhering to the card substrate is fed for being cooled down before the transfer film is separated from the card substrate. In the operation of separating the card substrate and the transfer film the regions of the transfer layer portion which have been embossed onto the card surface remain on the card substrate. The transfer film which is pulled off only still has on the carrier film the part of the transfer layer portion, which was not fixed on the card surface. After the embossing operation therefore this involves a carrier film with a transfer layer portion having holes, as a waste product.
The card substrates are usually fed to the apparatus with a transport device, transport chains involving a constant chain pitch frequently being employed. In that case the transfer film is used over a length corresponding to the respective chain pitch for each individual card, independently of the regions which are actually to be embossed out of the transfer film. After the embossing operation a relatively large remainder of transfer layer portion is left unused on the carrier film. In the case of a mass-produced item such as a card, in spite of the relatively high costs for transfer films, it is only possible to achieve low prices for each card so that card manufacture which is as economical as possible is required.
To make better use of a transfer film, a relatively complicated and expensive apparatus has already been proposed in accordance with EP 0 673 317 B1, in which the transfer film can be simultaneously used for embossing on a plurality of substrates arranged in mutually juxtaposed relationship in the transport direction, using a direction-changing arrangement.